The present invention is directed to a machine for continuously etching a surface of glass sheets, especially of big size, according to previously chosen patterns, by means of acid solutions.
It is known to use acids, in particular solutions of HF, in order to obtain glass sheets decorated with etchings on at least one face, by providing thereon a matrix of protective lacquer covering those areas which should not be attacked by the acid so as to form the negative of the pattern to be performed. When the glass sheets are of big size, considerable difficulties are met to put into contact with the acid all the points of the surface to be treated. The difficulties are especially due to the dangerous vapours issued, the important volumes of acid required and the scarce handiness of the sheets.
It is known that these inconveniences were already overcome by the previous Italian Pat. No. 817409 in the name of the present Assignee, but the apparatus forming its object however showed the disadvantage of enabling the treatment with acid in a discontinuous manner only, i.e. a glass sheet each time, as well as of having fixed sizes, which required the necessary availability of a number of equipments in order to be able to treat a plurality of glass sheet at the same time and/or of different size. This prior art apparatus, besides having a low productivity per hour, also required a large-scale employment of labour, with consequent high costs.